Landscape Architect Articles

A Park for the Garage01-17-18 | Feature

A Park for the Garage
Garage Park at City Square, Worcester Center

by Clara Batchelor, CBA Landscape Architects

In Worcester, Massachusetts, CBA Landscape Architects was hired to help revitalize the city center, including this plaza and park that sits above a new underground parking garage. This space is planned to be the major public open space of the new downtown. Currently, a lawn occupies the future site of a hotel.

Located 40 miles west of Boston, Worcester is the second largest city in New England with a population of approximately 185,000. With the growth of its biotechnical and healthcare facilities, Worcester is becoming a center of medical research and development. The city is reimagining and rebuilding its urban core to bring activity back and create an engaging city center. The city is investing in a new network of roads, public plazas, and an underground parking garage to attract more private development. Referred to as "CitySquare," the plan calls for residential, commercial and retail buildings to be integrated into the new downtown.

Landscape architecture firm CBA first worked with the architect, Arrowstreet, to design the landscape for the new Unum Insurance headquarters and for Mechanics Plaza, both within the re-envisioned downtown. CBA again joined with Arrowstreet to design the plaza and park at street level above the new underground parking garage. The garage park plaza is the major public open space of the redevelopment.

Precast concrete pavers (Unilock) in shades of gray and white make up the majority of the plaza, with the darker bands becoming denser towards the center of the area. Layered on top of the roof of the parking garage, from the bottom up, are waterproofing, drainage board and stone, light filler, filter fabric, compacted graded gravel, coarse aggregate, a rolled bituminous setting bed, and a neoprene tack coat, upon which the pavers sit.

The new plaza had two major challenges. First, the weight restrictions dictated by the underground structure limited the planting depth in most locations. The second was that about two thirds of the new plaza is to be permanent, while the remainder of the space is a "place holder" that will be replaced by a new hotel within the next several years. (Support for the weight of the future hotel was factored into the construction of that part of the garage.) The city wanted to minimize the cost where the future hotel is to be located. CBA's solution was to create a large lawn area.

For the permanent open space, CBA designed a paved plaza with cutouts for ornamental grasses and trees. The areas of ornamental grasses were raised to allow for increased soil depth, as were the beds for trees. The location of the trees was dictated by the load bearing capacity of the structure below. The shape of the raised planting beds was defined by pathways representing the desire lines for pedestrians crisscrossing the plaza.

The planted areas were raised slightly to allow for an increased soil depth, which was limited by the underground parking garage. Though drought tolerant plants including bristleleaf sedge and sheep fescue were specified, an irrigation system was installed to assuage concerns that the shallow soil might dry out the growing environment.

The paved surface is a pattern of 4" by 8" gray and white precast concrete pavers by Unilock. The pavers are set with a neoprene tack coat on top of a rolled bituminous setting bed, below which is a 2 ½" coarse aggregate bituminous layer above compacted graded gravel. Under that is a system of filter fabric, light filler, drainage stone, drainage board and waterproofing that was specified by the architect and sits directly on the roof of the underground parking garage.

The largest areas of pavement are concentrated around the two head houses that connect the plaza to the parking garage. The city wanted plenty of unobstructed paving for future programmed activities, including farmer markets, musical entertainment and street performers.

In response to vandalism in the downtown that had damaged site furniture, the seat walls around the raised planting areas feature a series of beveled and stepped granite blocks.

In an effort to deter skateboarders and vandals, the granite seatwalls were designed with ups, downs, angles, and a beveled edge. Dumor 93 series benches (visible in the leftmost photo) provide additional seating areas.

The ups, downs and angles were created to discourage skateboarders who have damaged other amenities throughout the city where skate blocks had proven ineffective. Stepped blocks were also placed in front of the larger head house, where the roof supports angle out low to keep pedestrians from walking into the low overhang of the roof.

Construction of the surrounding buildings is ongoing. When they are complete, Garage Park will be a focal point for the surrounding new development, providing space for programmed activities and informal gatherings. The new CitySquare area will be the heart of a revitalized vibrant downtown Worcester.

As seen in LASN magazine, January 2018, Hardscapes.